The air in Reisterstown came alive with the sound of chain saws and hammers today as hundreds of residents began to clean up the wreckage left by a tornado that devastated their homes.

Baltimore County police estimated the damage at $15 million, with as many as 170 houses and 500 people affected.

Hospital officials said seven people were treated for chest pains or storm injuries. Only two remained in hospitals overnight.

The only serious injury reported was to Dudley Cook, 58, of the Chartley Park Apartments on Glyndon Drive. Cook watched from his bed as the storm tore out the windows of his third-floor apartment, sheared off his roof and then collapsed the walls on top of him.

Sinai Hospital spokeswoman Vicki Hunter said Cook suffered a fractured pelvis, a broken leg and severe scalp lacerations. He was listed today in fair condition after surgery last night.

Baltimore County police spokesman Sgt. Stephen A. Doarnberger said 59 people were displaced by the storm, and as many as 60 others were injured.

Forty of the displaced found shelter with friends and relatives. Nineteen members of eight families were taken by the Red Cross to a Days Inn in Westminster, police said.

The Red Cross estimated it would spend up to $50,000 to house, feed and clothe victims, and help them replace lost personal items.

There was no immediate word on how many houses were being condemned.

State Police spokesman Chuck Jackson said 18 units at Chartley Park Apartments alone had been condemned; eight could be entered only with police and extreme caution.

Where damaged houses could be entered today, neighbors were helping neighbors haul out armloads of goods.

The restrictions didn't sit well today with such Chartley residents as Deborah Beaumont, 26, who said, "I don't want to hear about the ones we can't enter. If we can't enter it, they ought to bring our stuff out to us."

Lisa and Brett Mader, both 27, were given 20 minutes to gather belongings from their Bentley Park apartment, escorted by county police.

They fed their fish and gathered up clothes, perishable food and their children's Nintendo set.

"This will give them something to do today," Brett Mader said. The children normally attend Glyndon Elementary School, which was closed by a power outage.

Nearby, a metal chimney blown from a building across the street rested in a window of a second-floor apartment in the Maders' building. The entire roof of another building across the street lay shattered on their lawn.

Stephen Goodwich, 42, a nine-year resident of Bentley Park Apartments, said that while his basement apartment wasn't damaged, his building lost its roof, and he had to leave. "The situation is: Where am I going to have to move to?" he said.

The tornado touched down at 4:29 p.m. yesterday, lasted less than three minutes and traveled a path about one-eighth of a mile long and 100 yards wide, said Fred Davis, of the National Weather Service at Baltimore-Washington International Airport.

But destruction caused by the tornado covered a much larger area, the result of debris being tossed about by accompanying winds.

"It was a real mess," said George H. Zink, 57, a resident of Glyndon for 26 years. "My wife and I were in the kitchen talking and I looked out the window and saw the heavy rains and later roofs being blown off.

"The kitchen window blew in and shattered glass. . . . My wife [lay] on the floor and I [lay] on top of her," Zink said last night at the Reisterstown Volunteer Fire Station on Main Street, where the couple had taken temporary shelter.

"But next door, the wind blew the roof right off the house," he said. "Luckily nobody was in the house."

Alverta Payne, 80, whose apartment at 115 Glyndon Drive was destroyed, said she was in her living room when portions of her roof fell on her.

Minutes later, she was pulled from the debris by two unidentified teen-agers who heard her cries for help.

"I didn't even have time to pray," Payne said.

In all, the storm cut power to more than 81,900 Baltimore Gas & Electric Co. customers. The tornado and accompanying winds of 75 to 100 mph felled hundreds of trees onto power and telephone lines and snapped wooden utility poles like matchsticks.

Power was restored to all but 6,500 customers in the entire area by noon, including 4,000 in all of Baltimore County. BG&E spokeswoman Peggy Mulloy said all service would be restored by midnight, even in the tornado area.

The scene along Glyndon Drive, Shirley Manor Road, Chartley Drive, Northway Drive and Valley Meadow Drive resembled "Charleston in miniature," said Jackson, a reference to the South Carolina city devastated last year by Hurricane Hugo.

Traveling from southwest to northeast, winds hit the Chartley Shopping Center, tearing the roof off the Super Fresh market and damaging other stores and nearby houses along Chartley Drive.

Davis, confirming the tornado, said a funnel cloud then touched the earth beyond the stores.